Separate reports by real estate brokers, Brown Harris Stevens and Halstead Property, both showed the average sale price of a Manhattan apartment had risen to $1.43 million during the period.

The Manhattan market was largely boosted by increased demand for high-end apartments, which comprised a larger share of the market in the latest quarter.

"In the three-bedroom and large category, all of the areas posted increases with the East side and the West side showing double-digit increases in the average price for larger apartments," said Diane Ramirez, president of Halstead Property.

Those apartments were particularly sought after as growing families chose to stay in the city and trade up, said Pamela Liebman, Corcoran's CEO.

More international buyers also entered the scene, Liebman said, boosting demand for second homes in the $6 million to $12 million range.

"When you look at the top of the market, there were 28 sales $10 million and above and that was the highest number since 2008 pre-Lehman," said Jonathan Miller, president and CEO of Miller Samuel, a New York appraisal firm.

The most notable sales of the quarter were an Upper East Side townhouse owned by Sloan Lindemann Barnett and Roger Barnett that sold for about $47 million and a condo at the Plaza Hotel that was bought by Russian composer Igor Krutoy and his wife Olga for $48 million.

"Although prices are up, this is due to an unusual number of sales at the high end of the market," said Hall Willkie, president of Brown Harris Stevens residential sales. "If we discount these high-end sales, I believe the average price in most categories would essentially remain stable."

The median price, which measures the middle of the market and is less impacted by the high end, rose 4% to $830,000 in the second quarter, up from $800,000 in the previous period, Corcoran said. According to Brown Harris Stevens and Halstead, the median price slipped 1% over the past year to $835,000.

Still, the Manhattan housing market is considerably off its peak. Back in late 2008, buyers paid an average of about $1,400 a square-foot for a condo or co-op. The average price this year is a little more than $1,000 a square-foot.

In addition, the Halstead report noted that buyers paid 96% of the asking price. Although inventory was low, Manhattan apartments spent 130 days on the market during the second quarter compared to 112 days a year ago.